A conventional "open throat" crimping machine is usually no more than a converted C-frame hydraulic press. Such crimping machine uses a straight up and down pressing motion, and the tool that performs the crimping converts the straight motion into a radial pressing movement. The tool is mechanical in the sense that each segment of the tool is pressed more or less, depending upon its radial position. To achieve the open throat configuration, the tool essentially is considered to have been cut in half so that a number of die segments of the tools are secured to the top of a die cage while a corresponding number of die segments are secured to the bottom of the die cage. To operate, the upper die segments are lifted up so as to create an opened position to allow a workpiece to be loaded from the side of the machine. Once the workpiece is loaded, the upper die segments are driven downwards to thereby work cooperatively with the lower die segments to crimp the workpiece.
Thus, such conventional open throat crimping machine can only operate in two cycles, i.e., an upward movement to move the upper die segments to an opened positioned, and a punch cycle in which the upper dies are lowered to press the workpiece. Accordingly, for every pressing operation, the upper die segments have to be opened to its full opened position, irrespective of how big or small the to be crimped workpiece is.
Moreover, insofar as each of the upper and lower die segments for a conventional open throat crimping machine has to be individually mounted to the die cage, each die segment must be laboriously removed from the cage assembly in order that the dies be changed. Otherwise, a completely new cage assembly must be used for each different crimping operation.
Another type of prior art open throat machine uses mechanical linkage, applied horizontally, to the tapered surfaces of the crimp dies for crimping. This type of machine can only be top loaded and the replacement of the crimp dies necessitate a great deal of disassembly and assembly time.